title: Does allergic rhinitis make a difference to the respiratory resistance and reactance of asthma?
abstract: BACKGROUND
  Concomitant allergic rhinitis (AR) in asthmatic patients can contribute to increased asthma exacerbations and poorer symptom control. A recent study indicated that impulse oscillometry is a more sensitive measure of change in airway function than spirometry, but this has not been used to compare asthmatic patients with or without AR.
  
  
  OBJECTIVE
  We used impulse oscillometry (Mostgraph-01) to examine the impact of AR on asthma.
  
  
  METHODS
  Impulse oscillometry and spirometry were assessed in 50 patients with asthma only and 95 patients with asthma and AR.
  
  
  RESULTS
  Mean age in the asthma only group was significantly higher than in the asthma with AR group. Therefore, analysis of covariance adjusted for age was used to compare between these two groups. Percentage of mean forced expiratory volume in 1 s (FEV1), respiratory resistance at 5 Hz (R5) minus respiratory resistance at 20 Hz (R20), and resonant frequency (Fres) in the asthma with AR group were significantly less severe than in the asthma only group. Parameters of resistance and reactance were correlated with age and body mass index only in the asthma with AR group but not in the asthma only group. Correlations were observed between rate of change of maximum mid-expiratory flow and impulse oscillometry values of R5 and Fres in the asthma only group, but not between the rate of change of FEV1 and impulse oscillometry values.
  
  
  CONCLUSIONS
  Asthma with AR was associated with higher lung function and better values of resistance and reactance than asthma only.
authors.affiliation: Division of Medicine for Allergic Disease, Osaka Prefectural Medical Center for Respiratory and Allergic Diseases, Habikino city , Osaka , Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Matsuno
authors.forename: Seijiro
authors.initials: S
authors.lastname: Minamoto
mesh_terms: D001249:Asthma / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009991:Oscillometry / Q000379:methods / Q000592:standards; D065631:Rhinitis, Allergic; D012221:Rhinitis, Allergic, Perennial / Q000503:physiopathology*; D013147:Spirometry / Q000379:methods / Q000592:standards; D018709:Statistics, Nonparametric